Most women who use Mirena don’t suffer serious side effects. Common IUD side effects, such as mild cramping or bleeding, may last anywhere from a few hours to days after implanting the birth control device.
Other side effects may last for years but are not cause for concern. For example, about 20 percent of women who use Mirena stop having their period after a year. When a woman stops using the IUD, her period usually comes back.
While rare, some women reported serious side effects. For example, ectopic pregnancy and infection are life-threatening side effects that require immediate treatment. In some cases, women may need to have surgery.
In Mirena lawsuits, women said the device migrated from its proper location and resulted in organ perforation and ectopic pregnancy.
“[The side effect] you experience really depends on how sensitive you are to man-made or synthetic progesterone hormones and that will be different from woman to woman.”
A search of the FDA Adverse Event Reporting System (FAERS) Public Dashboard on July 16, 2018, showed the U.S. Food and Drug Administration received 91,265 reports of Mirena side effects from December 2000 to March 2018. A total of 37, 990 reports involved serious cases. That figure includes 131 deaths.
About 2 million American women use Mirena, according to Bayer’s brochure dated July 2011. Bayer used the same figure in its July 2012 Mirena Welcome Kit. An estimate is not apparent in the company’s more recent promotional materials.
Common Mirena Side Effects
The majority of women experience mild side effects. These include minor pelvic pain or cramping after Mirena insertion. Many of these go away after a few months.
- Abdominal/pelvic pain
- Back pain
- Bleeding and spotting between periods
- Breast tenderness or pain
- Changes in hair growth
- Changes in mood
- Heavier bleeding during the first few weeks after device insertion
- Itching or skin rash
- Loss of interest in sex
- Missed periods (amenorrhea)
- Ovarian cysts
- Weight gain
Bleeding, Ovarian Cysts and Breast Tenderness
Some women experience hormonal side effects from Mirena. These occur when the body is getting used to the hormones in the IUD. These include bleeding, ovarian cysts and breast tenderness.
During the first three to six months after receiving the IUD, periods may be lighter or heavier. Then, they may stop altogether.
Bayer estimates that two out of 10 women who use Mirena will stop having their period after one year. Women should still see their doctor to rule out pregnancy. If bleeding remains heavier than normal or becomes heavy after being light, women should call their doctor.
About 12 out of 100 women using Mirena develop cysts on their ovaries. Ovarian cysts happen when follicles on the ovary grow.
Most cysts go away on their own after one or two months, according to Bayer. But if they cause pain, a doctor may have to surgically remove them.
More than 5 percent of women who used the device in clinical trials reported breast pain or tenderness, according to the Mirena label. This is a common adverse effect of hormonal contraceptives and, according to researchers at the David Geffen School of Medicine, not significantly different among combined oral contraceptives. If pain is severe, women should see their doctor.
Device expulsion — shifting in the uterus or falling out — is the most reported side effect. It can happen any time after insertion, but it usually happens within the first few months.
A doctor can replace it after checking for pregnancy. Women should contact their doctor immediately if they experience symptoms that make them suspect the device is no longer in place, including bleeding, pain, heavier menstrual flow and cramping.
In a 2006 article published in American Family Physician, authors compared expulsion rates between levonorgestrel-releasing IUDs and copper IUDs. They found the rate of expulsion for hormonal devices was lower — 5.8 percent versus 6.7 percent. Women who have had a baby less than six weeks before inserting Mirena have a higher risk of expulsion.
Perforation occurs when the IUD cuts through the wall of the uterus. About one in 1,000 women with an IUD can suffer from perforation, according to a study published in the journal Contraception. Signs of perforation include severe abdominal pain, bleeding and disappearance of the IUD string. Perforation can cause scarring or organ damage.
Perforation can happen during the insertion process or any time after. Women who suffer severe abdominal pain, vaginal bleeding and cannot find the IUD string might have had a perforation. Perforation happens more often in women who are lactating or gave birth within six months of receiving Mirena, according to a 2012 study in RadioGraphics.
In a study presented at the 2014 American College of Obstetricians and Gynecologists meeting, data showed that among 61,000 women from six countries, perforation occurred more often with levonorgestrel IUDs than with copper IUDs.
Of the participants, 70 percent used a levonorgestrel IUD and 30 percent used a copper IUD.
Sixty-one women suffered perforation with the hormonal IUD versus 20 women using the copper IUD. Study authors did not consider the difference “clinically relevant.” They found the relative risk of perforation to be 1 in 1,000 insertions.
Migration or Displacement
Migration or displacement occurs when Mirena moves to another place in the body. This can happen after Mirena perforates the uterine wall and leaves the uterus. However, sometimes doctors don’t find evidence of perforation.
Migration may lead to embedment, which occurs when the IUD gets stuck in other parts of the body. For example, in a 2016 issue of the International Journal of Surgery, doctors reported a migration case. The IUD got stuck in the lining of the abdomen and required surgery.
A 2011 case study in the Journal of the Society of Laparoendoscopic Surgeons detailed two instances of Mirena migration that ended in surgery. In the first case, a 44-year-old mother of two had no symptoms, but the IUD strings were missing. Surgeons found the IUD in her right hip area surrounded by scar tissue.
In the second case, a 19-year-old received her Mirena after an abortion. Ten days later she went to the hospital with severe pain. Doctors did emergency surgery and found the IUD in her diaphragm.
Pelvic Inflammatory Disease and Infection
Less than 1 percent of Mirena users get a serious infection called pelvic inflammatory disease (PID). This condition can cause bleeding, vaginal discharge, abdominal pain, chills, fever and pain during sex. It requires immediate treatment. The highest risk of PID usually occurs within the first 20 days after Mirena insertion.
The IUD does not actually cause or increase the risk of infection. Usually, it occurs if there is already bacteria present in the vagina or if bacteria contaminate the IUD during insertion. Unprotected sex while using Mirena can increase the risk of PID. Women with multiple sex partners who use an IUD are at increased risk.
Rarely, a life-threatening infection called sepsis can occur a few days after insertion. Bayer said it has received nine reports of sepsis since September 2006. Women with severe pain or unexplained fever should call their doctor immediately.
Unexpected Pregnancy & Ectopic Pregnancy
Over a five-year period, about eight in 1,000 women became pregnant while using Mirena, according to Bayer’s Mirena Welcome Kit. This can be life threatening. It may also cause loss of fertility. Study results on ectopic pregnancy risk are mixed.
“In patients becoming pregnant with an IUD in place, septic abortion — with septicemia, septic shock, and death—may occur.”
A 2016 study in the International Journal of Women’s Health found that ectopic pregnancies — a life-threatening emergency that occurs when the fetus grows outside the uterus, usually in the fallopian tube — were more likely for women using hormone-releasing IUDs than for those using copper IUDs.
But in a 2014 study funded by Bayer, researchers said the risk of unintended pregnancy and ectopic pregnancy was higher with copper IUDs.
The study of 61,448 women found the risk of unintended pregnancy was 84 percent lower with levonorgestrel-releasing IUDs versus copper, and the risk of ectopic pregnancy was 74 percent lower.
- Sharp pain in the abdomen or pelvis
- Vaginal bleeding
- Rectal pressure
- Bladder or bowel problems
Pseudotumor cerebri means “false brain tumor.” It is also known as intracranial hypertension. This condition mimics the symptoms of a brain tumor. It can happen at any time with Mirena.
A 2015 study in Therapeutic Advances in Drug Safety looked at FDA data. It found increased reporting of pseudotumor cerebri with Mirena.
“We found a higher than expected number of reports of [intracranial hypertension] with Mirena. We also found a similar risk of ICH with Mirena compared to oral contraceptive EE-norgestimate,” authors wrote. “In light of these recommendations and the possible increase in the use of [intrauterine levonorgestrel (IUL) devices], the risk of ICH with Mirena must be clearly conveyed to young women who are planning to use them.”
If left untreated, the condition can cause permanent blindness. Treatments include weight loss, medication and surgery.
Please seek the advice of a medical professional before making health care decisions.